On University of Utah campus, where foot traffic goes all night long, a push against light pollution

(Steve Griffin | The Salt Lake Tribune) Traditional lighting creates glare near student housing, front, on the University of Utah campus in Salt Lake City. A "hooded" fixture, which directs light toward the ground, stands at the center of the scene.

With large buildings packed together, stadiums beaming like beacons and prolific street lamps for night-owl students, college campuses can be major culprits in light pollution.

The University of Utah is trying to reduce its glare with a yearslong project to replace and reform campus lighting — especially old “lollipop-style” street and path lights that beam intense rays in all directions from globe-shaped fixtures on posts.

Conventional lights and older LED lights have been so bright that they keep people awake, confuse birds, insects and other wildlife — and, paradoxically, make it harder to see at night. Dimmer lights may actually improve safety, Willson said.

“Wasteful lighting can be too glary in some places and dark in between the fixtures,” Willson said. “If it’s done properly, it’s a safer environment. With lower levels, your eyes will adjust. You can see better; the color rendition is better.”

The school has modified about 1,800 of 3,000 outdoor light fixtures, said Bill Leach, sustainability project coordinator. Since 2006, crews have been upgrading light fixtures with “hoods” that direct light toward the ground, and, in 2013, they began introducing hooded LED lights, which should pay for themselves in energy savings, said Willson.

“If we do it correctly,” Willson said, “it saves money and prevents energy waste, so it ties into our climate commitment.”

Now the school is working with consultants to optimize the brightness and hue of the LED lights, Willson said. Lights that are too bright or too blue have been shown to interfere with sleep and cause fatigue.

“We’ve gone through phases as we’ve learned more and as the products have become better,” he said.

The school also is installing dimmers in some lights to reduce glare even more after 11 p.m.

“Even if you have a hooded light, if it’s overlit, the whole area kind of glows,” Willson said, “and it bugs the neighbors and wildlife.”

The transition aligns with a citywide effort, spearheaded by Tracy Aviary, to limit outdoor lighting from 11 p.m. to 6 a.m. during spring and fall bird migrations.

Each of the 3,000 light fixtures on campus costs at least $2,000 to change — which is why it has taken several years.

“We do it incrementally,” Willson said. “We have a lot of fixtures from decades of campus development that we have to correct.”